The Surgery and Transgenic Mouse Core (Core B) will provide state-of-the-art support to all four Projects with studies involving surgical procedures in murine models and use of transgenic/knockout mice. The Core will consist of two Units, the Surgery Unit, which will be responsible for all surgical procedures, and the Transgenic Mouse Unit, which will be responsible for generating, breeding, and genotyping the various lines of transgenic and knockout mice. These two Units will be inextricably intertwined, as the Transgenic Unit will produce the mice operated on by the Surgery Unit while the Surgery Unit will phenotype the mice generated by the Transgenic Unit. Dr. Yiro Guo, an expert surgeon, will be Leader of Core B and will be specifically responsible for all operations in the Surgery Unit. Dr. Gregg Rokosh, an expert molecular biologist, will be Co-Leader of Core B and will be specifically responsible for the functions of the Transgenic Mouse Unit. The complementarity of their backgrounds, coupled with their collegial nature, provides a strong foundation for productive synergy. The Surgical Unit of Core B will perform coronary artery occlusion/reperfusion studies, measurements of infarct size, gene transfer procedures, administrationof pharmacologicagents, perfusion fixation of cardiac tissue, and noninvasive and hemodynamic studies. It will also generate myocardial tissue samples as well as cardiomyocytes to be used for molecular studies. State-of-the-art facilities and equipment are available. All Core personnel have extensive experience with the murine models of myocardialinfarctionand gene therapy to be used in the four Projects. These procedures have been performed in over 9,000 mice and are associated with minimal complications. The postmortem perfusion technique to measure infarct size results in accurate delineation of the infarcted area, area at risk, and nonischemic area, such that measurements of infarct size are highly reproducible. Meticulous attention is paid to maintaining fundamental physiologic parameters (heart rate, arterial blood pressure, arterial blood pH, hematocrit, and body temperature) within normal limits throughout the coronary occlusion/reperfusionstudies. The protocol for gene delivery (i.v. infusion of viral vectors with distal aortic clamping under whole-body hypothermia) results in widespread, highly efficient transduction (70-90%) of cardiomyocytes throughout the left ventricle. The Core is equipped with fully functional echocardiography and invasive hemodynamic laboratories for accurate assessment of LV function in vivo. The Transgenic Mouse Unit of Core B will provide 14 transgenic or knockout mouse lines to be used by the four Projects. The Unit has already created several transgenic mouse lines with cardiac-specific gene expression, including a novel inducible knockout of STAT3, and will create new genetically-engineered models that will allow temporal control of transgenic expression. The Unit will also be responsible for breeding, genotyping, and handling all of the transgenic and knockout mice to be used in the four Projects. For knockout mice, controls will consist of wild-type littermates generated by Het x Het inbreeding;similarly, wild-type littermates will be used as controls for transgenic mice. In summary, Core B will provide a strong backbone for this Program Project. The extensive experience of the personnel, the superb facilities available, and the strong collegiality of the investigators will provide the four Projects with an outstanding experimental resource to undertake physiologically-relevant studies pertaining to the protection of ischemic myocardium.